a) Field of the Invention
The present invention relates to both a method and a device for removing ecologically noxious Volatile Organic Compounds (VOC) from gaseous streams in conduits, chimneys and/or exhaust ducts. The method is based on the principle of the direct oxidation of VOC by ozone and is especially useful in eliminating a large variety of organic odorous pollutants, such as mercaptans and others sulfurous compounds, by converting them into non-harmful, environmentally friendly products.
b) Description of the Prior Art
To carry out the elimination of Volatile Organic Compounds (VOC) and other organic compounds from gaseous effluents, it is known to adsorb them with activated carbon or with a fibrous bed. It is also a common practice to use aqueous solutions to scrub the gases and thereby remove the VOC. Another method is to bum and destroy the VOC by the action of heat, combined or not with metal catalysts, using a thermal incinerator. The problems related with these methods are numerous. The activated carbon adsorption method requires frequent regeneration (steam, hot nitrogen or thermal) and regular replacement of the activated carbon. The water scrubber method requires the separation of the solvents from the soiled water prior to their reintroduction into the scrubber while the thermal incineration requires the burning of fuel to maintain an appropriate temperature inside the incinerator. Accordingly, all of these known methods not only demand high capitalization costs but they are further very expensive to operate.
A simpler approach is the use of High Energy Corona (HEC) which permits the removal of ecologically noxious substances from gases at relatively low temperatures. U.S. Pat. Nos. 5,542,967 and 5,601,633 disclose respectively an apparatus and a method using an electrical precipitator wherein a stream of gases is subjected to micro plasma discharges. These electrical discharges break down the VOC into carbon and other by-products like a micro-incinerator. However, the method and apparatus described in these two patents are expensive to use due to their high energy demand. They are furthermore different from the present invention in that they require a power supply and a multi-stage Fitch generator in order to provide the very high voltage necessary to produce the electrical discharges. They also aim in producing highly active intermediate substituents other than ozone.
Recently, U.S. Pat. No. 5,573,733, disclosing an ozone generator was granted to the present inventor. The technology behind this ozone generator is innovative and could be used in the treatment of gaseous effluents. By creating a very oxidizing environment one could fully or partially break down the organic pollutants contained in gaseous effluents and transform these pollutants into more environmentally friendly products such as H2O, CO2 and SO2.
Accordingly, there is thus a need for a simple, efficient and cheap reactor and method thereof which are based on the use of ozone for the treatment of polluted gaseous effluents. The present invention fulfils these needs and avoids or overcomes the various previously mentioned disadvantages of the prior art. The present invention also fulfils other needs as will be apparent to those skilled in the art upon reading the following specification.